 

 var STBackgroundLayer = cc.Layer.extend({

 	  ctor : function(){
 	  	this._super()
 	 	
 	 	this.initBackground();
 	  },

 	  initBackground : function(){

 	  	this._sptBg = new cc.Sprite.create(res.mm_bg_png);
 	  	this._sptBg.attr({
  	   		x: GC.w_2, 
  	   		y: GC.h_2
 	  	});
 	  	this.addChild(this._sptBg);
 	  }
 });